The present invention relates to a toroidal type continuously variable transmission.
Japanese Utility Model Provisional Publication No. 63-92859 shows a conventional transmission of such a type. This transmission has input and output cone discs forming a toroidal cavity therebetween, and power rollers installed in the toroidal cavity so as to transmit torque from the input disc to the output disc. One or more actuators are provided to incline the power rollers to continuously vary a transmission ratio.
This conventional transmission is mounted on a vehicle, and the output disc is connected to a forward-reverse changeover mechanism to change the direction of rotation to drive the vehicle in the reverse direction as well as in the forward direction. In this conventional system, the forward-reverse changeover mechanism is provided on the output side of the toroidal transmission. Therefore, a very heavy torque is applied to the forward-reverse changeover mechanism especially when the toroidal transmission is shifted toward a lower speed. The forward-reverse changeover mechanism of this conventional system therefore needs to have a large torque capacity and a large size. A similar arrangement is disclosed in Japanese Patent Provisional Publication No. 63-130954.
When, on the other hand, the forward-reverse changeover mechanism is provided on the input side of the toroidal transmission to reduce the size of the changeover mechanism (as shown in Japanese Patent Provisional Publication No. 62-255652), then there arises a need for changing the direction of inclination of the power rollers depending on the direction of rotation inputted to the input disc.